Prime minister John Key says New Zealand will abide by a new global climate change deal, but the commitments the Government signs up to will depend on other countries.

About 200 nations - including the biggest polluters China, India and the US - yesterday signed up to a treaty to reduce emissions.  The deal replaces the Kyoto Protocol and must be in place by 2020.

It was signed in Durban, South Africa after two weeks of talks which almost collapsed after wrangling over the text.

New Zealand must decide whether to join Europe in setting down commitments within the Kyoto Protocol framework or to join developing countries, the US, Canada, Japan and Russia in making other arrangements in different texts.

Key said the government will take stock of what other countries do. 

''We set a number of conditions around our target and we also said those conditions were quite contingent on other countries joining us, in terms of what obligations they would abide by.''

He added: ''I think its plain to everyone that with the economic conditions being very challenging, particularly in the US, and to a lesser extent Europe that is causing some degree of trepidation at least by those leaders.''

Climate change negotiations minister Tim Groser said: "This agreement meets all the realistic expectations the New Zealand delegation had when it arrived in South Africa two weeks ago."

The deal maintains the structure of Kyoto but improves rules around land use and forestry.

''These changes have environmental integrity and make more sense for New Zealand,'' he said.
 
Groser said New Zealand's negotiating team worked with Australian counterparts, led by Australian  climate change minister Greg Combet.
 
In a joint statement from Groser and climate change minister Nick Smith, they said: ''It is not a matter of whether we make commitments - New Zealand will - but where they are made and how ambitious we should be.
 
"Like all countries, we will need to take account of our national circumstances and compare our efforts to the efforts of others. We want to do our fair share, but it will not be clear for some time what exactly others will be committing to.''

However the deal has been dismissed by environmentalists as too little too late.

The Worldwide Fund for Nature's New Zealand branch says it won't stop a two degree increase in the world's temperature and the 2020 deadline is too far away.

Its climate change campaigner Peter Hardstaff told breakfast television this morning that New Zealand wants to change the rules so it could cash in on carbon credits after reducing emissions though extensive tree planting.

The credits could be sold on to other countries, allowing them to discharge great amounts.

Oxfam New Zealand says the pact will do little for the poorest nations in the Pacific which are already suffering the effects of climate change.

- Fairfax NZ